This invention relates to the treatment and/or prevention of dermatitis originating from the toxin urushiol which has been found to be present in poison ivy, poison oak, poison sumac, and the like.
A discussion and description of poison ivy dermatitis dates back to Chinese medical books of the seventh century. The first chemical experiments made in the United States on the toxin itself occurred over 100 years ago in 1858. The experimentor, Khittel, concluded that the poison was a volatile alkaloid, see Khittel, Am. J. Pharm., 6(3), 542 (1858). It was not until the early 1930's that the carbon skelton of the irritant causing poison ivy dermatitis, known as urushiol, was defined by Hill and his students at Wesleyan University, see Hill, G., Mattacotti, V., and Graham, W.; "The Toxic Principle of Poison Ivy", J. Am. Chem. Soc., 56:2736, (1934). Urushiol was defined to be within the catechol group.
Poison ivy, poison oak, or poison sumac, upon contact with the skin causes severe inflamation, irritation, and blistering in certain individuals. Various enzymes and compounds have been proposed as a means of treating poison ivy dermatitis. Zirconium oxide is such a material; however, it has been frowned upon by the medical profession because of its allergic reactions in hypersensitive individuals. Additional agents such as potassium permanganate, hydrogen peroxide, and tyrosinase have been proposed; however, all have drawbacks either dealing with response time or toxicity. Applicants note Borris, U.S. Pat. No. 4,002,737, disclosing an enzyme catechol 1,2-oxygenase and catechol 2,3-oxygenase and mixtures thereof used in the detoxification of urushiol. Borris teaches that urushiol is detoxified by the enzyme catechol 1,2-oxygenase to an alkylated derivation cis, cismuconic acid. Catechol 2,3-oxygenase, which is also disclosed by Borris as a detoxifying agent of urushiol, results in a non-toxic alkylated derivative of alphahydroxy muconic semialdehyde when combined with urushiol. However, experiments have indicated that catechol 2,3-oxygenase is unstable in the presence of air. Its practical application as a drug in treating poison ivy dermatitis is questionable. See Boyer, P.D., The Enzymes, Vol. XII, p. 140, Academic Press, N.Y., N.Y. (1975). Borris discloses a mixed function oxidase reaction wherein the catechol is oxidized and the benzene ring structure is split within the reaction.
In addition to the Borris reference and articles disclosed therein, applicants note Sizer, I. W. and Prokesch, C. E.; "The Destruction by Tyrosinase of the Irritant Principles of Poison Ivy and Related Toxicants", J. Pharm. & Exper. Therap., 84:363, (1945). Tyrosinase is known in the art as a detoxifying agent of urushiol. Tyrosinase attacks both mono- and polyphenols in a mono-function oxidase reaction. The enzyme, active primarily against ortho-diphenols, oxidizes the o-diphenol resulting in an unstable di-ketone which eventually breaks down and polymerizes. Tyrosinase is an endo-enzyme. It does not normally react in an aerobic environment but, rather, requires a closed cell reaction in a protective buffer environment. Because of this characteristic, the response time to treatment may be prolonged.